Gas springs are frequently used for assisting the movement of hand-operated movable construction units with respect to stationary construction units against gravitational forces. Gas springs are e.g. used for assisting the movement of boot lids and engine bonnets with respect to the respective vehicle. It is not always desirable that the gas spring is strong enough to lift the boot lid or the like without additonal manipulation by hand. In such cases the gas spring does not fulfil the function of holding the boot lid in the fully opened position if desired. Specific provisions are needed in view of this function to be fulfilled by the gas spring. These provisions made the gas springs rather complicated and expensive in the past.